Arabian Peninsula Nourished Civilization
Oddly enough, the same titanic forces that created the Arabian Desert at the head of this great rift system also nurtured the rise of Western civilizations and three of the world's dominant religions. North of the Red Sea, the Suez Canal connects directly to the Mediterranean Sea, which is shrinking as a result of the same movements that are opening up the Red Sea and shifting the Arabian Peninsula north. Eventually, Africa will slowly rotate and plow into Europe.
The unexpected side effects of the titanic forces that ripped the Middle East loose from Africa have sustained civilization. The split drove Arabia into Asia, pushing the small, dwindling Arabian plate down underneath Asia. The result was a huge, sallow sea. These shallow coastal waters provided the perfect home for plankton, algae, and other creatures that drifted and floated in the sunlit waters. When they died, their bodies sunk to the bottom, creating layers of mud rich in organic debris, along with the mud and rock washing in from the surrounding landmasses. This went on for millions of years. Periodically, the climate would shift due to small variations in the wobble of the Earth's orbit around the sun. During cold ice ages, the oceans would drop as huge quantities of water accumulated as snow and ice at the Poles. During warm periods, the polar ice would melt and the sea levels would rise. As a result, the ocean repeatedly invaded the shallow basin. When climate shifted and the ocean fell, it would leave behind a stranded, shallow sea that would eventually evaporate, leaving a thick layer of salt. Eventually, these salt layers sealed up the sediment trapped in the bottom of the basin.
Those buried mud layers laced with the remains of microscopic sea creatures plus the organic debris of the marshes and swamps that dominated the sunken area when the ocean retreated were capped by layers of salt and other sediment, trapping them in place deep beneath the surface. There, thousands of feet beneath the surface, the heat and pressure gradually transformed these buried organic deposits into oil and natural gas. This oil remained trapped by the cap of salt and sediment as the heating caused it to expand and press against the unyielding cap of sediment.
As a result, when geologists eventually drilled holes to penetrate these caps, the oil expanded into the pipes and drill holes to create oil gushers. The result was the vast oil fields of the Middle East that have fueled the world's economy and a succession of wars that have plagued the region in the past century.
The Arabian Desert harbors the world's largest single oil field, Ghawar, which is 174 miles (278 km) long and 16 miles (27 km) wide and contains an estimated 55 billion barrels of oil. Every day, oil companies pump out 5 million barrels, which makes the area vital to the economy of the gasoline-addicted world. Ghawar's oil is contained in 280-foot-thick (93 m) layers of limestone laid down in the late Jurassic period, but now some 7,000 feet (2,134 m) below the surface. A bulging anticline of anhydrite rock lies on top of the Ghawar limestones, trapping and pressurizing the oil beneath. Initially, the oil gushed from the wells under its own pressure, but as the oil companies pumped out more and more oil they had to start injecting millions of gallons of pressurized water back into the limestone layer to keep up the pressure. In addition, energy companies extract another 2 billion cubic feet of natural gas every day, mostly from shales 14,000 feet (4,700 m) beneath the surface. These shales were laid down in marshes and sea bottoms during the Silurian period, between 443 and 417 million years ago. At this time, Earth's climate warmed and stabilized, which melted much of the ice cap at either pole. Seas rose and flooded what would one day become the Arabian Desert, which led to the formation of the organic-rich shales on the seafloor. At about the same time, the first coral reefs developed and fish underwent major changes. The first fish with jaws emerged, as did the first freshwater fish.